I've had a 340 in my 65 Barracuda since 1973. Manual steering, 4 speed. I blew up the 273 trying to drive home from Charleston, South Carolina to Cochran, Georgia in second gear after I broke the 3-4 shift fork bar-hopping one last time before leaving for Viet Nam. While my ship was in Nam, my Dad bought a junkyard 340 from a wrecked 72 Charger and had a local garage install it. With 273 exhaust manifolds. I wanted to run 340 manifolds. The 1972 center dump passenger side fit OK, but the driver's side hit the steering joint. I cut the outlet in the middle of the curve, turned it around and had it re-welded. Now it cleared. That setup lasted years until I accidentally did a burnout in reverse and broke the manifold at the weld.
Got another manifold. This time I just removed the cap from the joint box and ground the top edges. Now it cleared. No cover over the grease, but it didn't seem to hurt anything. Ran it this way for years.
Finally, after I learned that power steering and manual steering shafts were different lengths, and the power steering shaft was shorter, I got the bright idea to swap in a power steering column and use a power steering column to manual steering box adapter. This moved the joint back out of the way, and I could put a new box and cover over the joint.
As for the pipe, only way I could figure how to go was run a 2.25 inch pipe from the manifold down between the torsion bar and the frame and then back. That just cleared, and never had a problem with it.
Have no idea about power steering clearance.
As for headers, I now have TTI's. You want easy, they aren't it. They fit, don't leak, and don't rattle, but it's a lot of work to get there, and lots of stuff (wiring, clutch linkage, brake lines, steering column, etc) had to be moved/re-routed/modified.
Have no idea about how well Doug's fit. At the time I went to headers, I was under the impression that Doug's wouldn't fit a four speed, but I've since heard different.
